text: When the glass is exposed to UV light with wavelengths between 280–320 nm, a latent image is formed. The glass remains transparent at this stage, but its ability to absorb UV light increases. This increased absorption is only detectable using UV transmission spectroscopy and is caused by an oxidation reduction reaction that occurs inside the glass during exposure. This reaction causes cerium ions to oxidize to a more stable state, and silver ions are reduced to silver.